Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.
A headache is a pain in the head, such as in the scalp, face, forehead or neck. A headache can be a primary headache or a secondary headache. A primary headache is a headache which is not caused by another condition. Contrarily, a secondary headache is due to a disease or medical condition, such as an illness, infection, injury, stroke or other abnormality. Thus, with a secondary headache there is an underlying disorder that produces the headache as a symptom of that underlying disorder.
Tension headache is the most common type of primary headache and accounts for about 90% of all headaches. A tension headache is often experienced in the forehead, in the back of the head and neck, or in both regions. It has been described as a tight feeling, as if the head were in a vice. Soreness in the shoulders or neck is common. Nausea is uncommon with a tension headache. Tension-type headaches can be episodic or chronic. Episodic tension-type headaches are defined as tension-type headaches occurring fewer than 15 days a month, whereas chronic tension headaches occur 15 days or more a month for at least 6 months. Tension-type headaches can last from minutes to days, months or even years, though a typical tension headache lasts 4-6 hours.
Migraine headaches are recurrent headaches that may be unilateral or bilateral. Migraine headaches may occur with or without a prodrome. The aura of a migraine may consist of neurologic symptoms, such as dizziness, tinnitus, scotomas, photophobia, or visual scintillations (e.g., bright zigzag lines). Migraines without aura are the most common, accounting for more than 80% of all migraines. An estimated 10-20% of the population suffers from migraine headaches. An estimated 6% of men and 15-17% of women in the United States have migraine. Migraines most commonly are found in women, with a 3:1 female-to-male ratio.
The typical migraine is unilateral (affecting one half of the head) and pulsating in nature and lasting from two to 72 hours. Symptoms include nausea, vomiting, photophobia (increased sensitivity to light) and phonophobia (increased sensitivity to sound).
The cause of migraines is unclear. Migraines vary between people and so does the treatment. Initial treatment is with analgesics for the headache, an antiemetic for the nausea, and the avoidance of triggers.
Preventive migraine drugs are considered effective if they reduce the frequency or severity of migraine attacks by at least 50%. Many medicines are available to prevent or reduce frequency, duration and severity of migraine attacks. Beta blockers, such as Propranolol, atenolol, and metoprolol; calcium channel blockers, such as amLodipine, flunarizine and verapamil; the anticonvulsants sodium valproate, divalproex, gabapentin and topiramate; and tricyclic antidepressants are some of the commonly used drugs. The major problem with migraine preventive drugs, apart from their transient nature and relative inefficacy, is that undesirable side effects are common. Such side effects include insomnia, sedation or sexual dysfunction.
Cluster headache is far less common than migraine headache or tension headache. The cluster headache exhibits a clustering of painful attacks over a period of many weeks. The pain of a cluster headache peaks in about 5 minutes and may last for an hour. Someone with a cluster headache may get several headaches a day for weeks at a time—perhaps months—usually interrupted by a pain-free period of variable length. In contrast to people with migraine headache, perhaps 5-8 times as many men as women have cluster headache. Most people get their first cluster headache at age 25 years, although they may experience their first attacks in their teens to early 50s. There are two types of cluster headache, episodic and chronic. The episodic type is more common and characterised by 2 or 3 headaches a day for about 2 months and then followed by a period of untreated sustained relief for a long period (e.g., a year). The pattern may then repeat. The chronic type behaves similarly to episodic but without the period of untreated sustained relief.
Trigeminal neuralgia is a neuropathic disorder characterized by episodes of intense pain in the face, originating from the trigeminal nerve. The disorder is characterized by episodes of intense facial pain that last from a few seconds to several minutes or hours. The episodes of intense pain may occur paroxysmally. Individual attacks usually affect one side of the face at a time and tend to occur in cycles with remissions lasting months or even years. Certain medicines sometimes help reduce pain and the rate of attacks. These medicines include anti-seizure drugs (carbamazepine, gabapentin, lamotrigine, phenytoin, valproate, and pregabalin), muscle relaxants (baclofen, clonazepam) and tricyclic antidepressants (amitriptyline, nortriptyline, or carbamazepine). Some patients may need surgery to relieve pressure on the nerve. Techniques include cutting or destroying part of the trigeminal nerve, stereotactic radiosurgery or surgery to remove a blood vessel or tumor that is putting pressure on the trigeminal nerve.
About 2% of all headaches are secondary headaches. For example, a cervicogenic headache is a headache which is due to a neck problem, such as an abnormality of neck muscles, which can result from prolonged poor posture, arthritis, injuries of the upper spine, or from a cervical spine disorder. Sinus headache is another type of secondary headache. A sinus headache can be caused by inflammation and/or infection in the paranasal sinuses.
It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.